﻿/*!
jQuery.kinetic v1.8.2
Dave Taylor http://the-taylors.org/jquery.kinetic

The MIT License (MIT)
Copyright (c) <2011> <Dave Taylor http://the-taylors.org>
*/
/*global define,require */
(function ($) {
    'use strict';

    var DEFAULT_SETTINGS = {
        cursor: 'move',
        decelerate: true,
        triggerHardware: false,
        y: true,
        x: true,
        slowdown: 0.9,
        maxvelocity: 40,
        throttleFPS: 60,
        movingClass: {
            up: 'kinetic-moving-up',
            down: 'kinetic-moving-down',
            left: 'kinetic-moving-left',
            right: 'kinetic-moving-right'
        },
        deceleratingClass: {
            up: 'kinetic-decelerating-up',
            down: 'kinetic-decelerating-down',
            left: 'kinetic-decelerating-left',
            right: 'kinetic-decelerating-right'
        }
    },
        SETTINGS_KEY = 'kinetic-settings',
        ACTIVE_CLASS = 'kinetic-active';
    /**
    * Provides requestAnimationFrame in a cross browser way.
    * http://paulirish.com/2011/requestanimationframe-for-smart-animating/
    */
    if (!window.requestAnimationFrame) {

        window.requestAnimationFrame = (function () {

            return window.webkitRequestAnimationFrame ||
            window.mozRequestAnimationFrame ||
            window.oRequestAnimationFrame ||
            window.msRequestAnimationFrame ||
            function ( /* function FrameRequestCallback */callback, /* DOMElement Element */element) {
                window.setTimeout(callback, 1000 / 60);
            };

        } ());

    }

    // add touch checker to jQuery.support
    $.support = $.support || {};
    $.extend($.support, {
        touch: "ontouchend" in document
    });
    var selectStart = function () { return false; };

    var decelerateVelocity = function (velocity, slowdown) {
        return Math.floor(Math.abs(velocity)) === 0 ? 0 // is velocity less than 1?
               : velocity * slowdown; // reduce slowdown
    };

    var capVelocity = function (velocity, max) {
        var newVelocity = velocity;
        if (velocity > 0) {
            if (velocity > max) {
                newVelocity = max;
            }
        } else {
            if (velocity < (0 - max)) {
                newVelocity = (0 - max);
            }
        }
        return newVelocity;
    };

    var setMoveClasses = function (settings, classes) {
        this.removeClass(settings.movingClass.up)
            .removeClass(settings.movingClass.down)
            .removeClass(settings.movingClass.left)
            .removeClass(settings.movingClass.right)
            .removeClass(settings.deceleratingClass.up)
            .removeClass(settings.deceleratingClass.down)
            .removeClass(settings.deceleratingClass.left)
            .removeClass(settings.deceleratingClass.right);

        if (settings.velocity > 0) {
            this.addClass(classes.right);
        }
        if (settings.velocity < 0) {
            this.addClass(classes.left);
        }
        if (settings.velocityY > 0) {
            this.addClass(classes.down);
        }
        if (settings.velocityY < 0) {
            this.addClass(classes.up);
        }

    };

    var stop = function ($scroller, settings) {
        settings.velocity = 0;
        settings.velocityY = 0;
        settings.decelerate = true;
        if (typeof settings.stopped === 'function') {
            settings.stopped.call($scroller, settings);
        }
    };

    /** do the actual kinetic movement */
    var move = function ($scroller, settings) {
        var scroller = $scroller[0];
        // set scrollLeft
        if (settings.x && scroller.scrollWidth > 0) {
            scroller.scrollLeft = settings.scrollLeft = scroller.scrollLeft + settings.velocity;
            if (Math.abs(settings.velocity) > 0) {
                settings.velocity = settings.decelerate ?
                    decelerateVelocity(settings.velocity, settings.slowdown) : settings.velocity;
            }
        } else {
            settings.velocity = 0;
        }

        // set scrollTop
        if (settings.y && scroller.scrollHeight > 0) {
            scroller.scrollTop = settings.scrollTop = scroller.scrollTop + settings.velocityY;
            if (Math.abs(settings.velocityY) > 0) {
                settings.velocityY = settings.decelerate ?
                    decelerateVelocity(settings.velocityY, settings.slowdown) : settings.velocityY;
            }
        } else {
            settings.velocityY = 0;
        }

        setMoveClasses.call($scroller, settings, settings.deceleratingClass);

        if (typeof settings.moved === 'function') {
            settings.moved.call($scroller, settings);
        }

        if (Math.abs(settings.velocity) > 0 || Math.abs(settings.velocityY) > 0) {
            // tick for next movement
            window.requestAnimationFrame(function () { move($scroller, settings); });
        } else {
            stop($scroller, settings);
        }
    };

    var callOption = function (method, options) {
        var methodFn = $.kinetic.callMethods[method],
            args = Array.prototype.slice.call(arguments)
        ;
        if (methodFn) {
            this.each(function () {
                var opts = args.slice(1), settings = $(this).data(SETTINGS_KEY);
                opts.unshift(settings);
                methodFn.apply(this, opts);
            });
        }
    };

    var attachListeners = function ($this, settings) {
        var element = $this[0];
        if ($.support.touch) {
            $this.bind('touchstart', settings.events.touchStart)
                .bind('touchend', settings.events.inputEnd)
                .bind('touchmove', settings.events.touchMove)
            ;
        } else {
            $this
                .mousedown(settings.events.inputDown)
                .mouseup(settings.events.inputEnd)
                .mousemove(settings.events.inputMove)
            ;
        }
        $this
            .click(settings.events.inputClick)
            .scroll(settings.events.scroll)
            .bind("selectstart", selectStart) // prevent selection when dragging
            .bind('dragstart', settings.events.dragStart);
    };
    var detachListeners = function ($this, settings) {
        var element = $this[0];
        if ($.support.touch) {
            $this.unbind('touchstart', settings.events.touchStart)
                .unbind('touchend', settings.events.inputEnd)
                .unbind('touchmove', settings.events.touchMove);
        } else {
            $this
            .unbind('mousedown', settings.events.inputDown)
            .unbind('mouseup', settings.events.inputEnd)
            .unbind('mousemove', settings.events.inputMove)
            .unbind('scroll', settings.events.scroll);
        }
        $this.unbind('click', settings.events.inputClick)
        .unbind("selectstart", selectStart); // prevent selection when dragging
        $this.unbind('dragstart', settings.events.dragStart);
    };

    var initElements = function (options) {
        this
        .addClass(ACTIVE_CLASS)
        .each(function () {

            var self = this,
                $this = $(this);

            if ($this.data(SETTINGS_KEY)) {
                return;
            }

            var settings = $.extend({}, DEFAULT_SETTINGS, options),
                xpos,
                prevXPos = false,
                ypos,
                prevYPos = false,
                mouseDown = false,
                scrollLeft,
                scrollTop,
                throttleTimeout = 1000 / settings.throttleFPS,
                lastMove,
                elementFocused
            ;

            settings.velocity = 0;
            settings.velocityY = 0;

            // make sure we reset everything when mouse up
            var resetMouse = function () {
                xpos = false;
                ypos = false;
                mouseDown = false;
            };
            $(document).mouseup(resetMouse).click(resetMouse);

            var calculateVelocities = function () {
                settings.velocity = capVelocity(prevXPos - xpos, settings.maxvelocity);
                settings.velocityY = capVelocity(prevYPos - ypos, settings.maxvelocity);
            };
            var useTarget = function (target) {
                if ($.isFunction(settings.filterTarget)) {
                    return settings.filterTarget.call(self, target) !== false;
                }
                return true;
            };
            var start = function (clientX, clientY) {
                mouseDown = true;
                settings.velocity = prevXPos = 0;
                settings.velocityY = prevYPos = 0;
                xpos = clientX;
                ypos = clientY;
            };
            var end = function () {
                if (xpos && prevXPos && settings.decelerate === false) {
                    settings.decelerate = true;
                    calculateVelocities();
                    xpos = prevXPos = mouseDown = false;
                    move($this, settings);
                }
            };
            var inputmove = function (clientX, clientY) {
                if (!lastMove || new Date() > new Date(lastMove.getTime() + throttleTimeout)) {
                    lastMove = new Date();

                    if (mouseDown && (xpos || ypos)) {
                        if (elementFocused) {
                            $(elementFocused).blur();
                            elementFocused = null;
                            $this.focus();
                        }
                        settings.decelerate = false;
                        settings.velocity = settings.velocityY = 0;
                        $this[0].scrollLeft = settings.scrollLeft = settings.x ? $this[0].scrollLeft - (clientX - xpos) : $this[0].scrollLeft;
                        $this[0].scrollTop = settings.scrollTop = settings.y ? $this[0].scrollTop - (clientY - ypos) : $this[0].scrollTop;
                        prevXPos = xpos;
                        prevYPos = ypos;
                        xpos = clientX;
                        ypos = clientY;

                        calculateVelocities();
                        setMoveClasses.call($this, settings, settings.movingClass);

                        if (typeof settings.moved === 'function') {
                            settings.moved.call($this, settings);
                        }
                    }
                }
            };

            // Events
            settings.events = {
                touchStart: function (e) {
                    var touch;
                    if (useTarget(e.target)) {
                        touch = e.originalEvent.touches[0];
                        start(touch.clientX, touch.clientY);
                        e.stopPropagation();
                    }
                },
                touchMove: function (e) {
                    var touch;
                    if (mouseDown) {
                        touch = e.originalEvent.touches[0];
                        inputmove(touch.clientX, touch.clientY);
                        if (e.preventDefault) { e.preventDefault(); }
                    }
                },
                inputDown: function (e) {
                    if (useTarget(e.target)) {
                        start(e.clientX, e.clientY);
                        elementFocused = e.target;
                        if (e.target.nodeName === 'IMG') {
                            e.preventDefault();
                        }
                        e.stopPropagation();
                    }
                },
                inputEnd: function (e) {
                    end();
                    elementFocused = null;
                    if (e.preventDefault) { e.preventDefault(); }
                },
                inputMove: function (e) {
                    if (mouseDown) {
                        inputmove(e.clientX, e.clientY);
                        if (e.preventDefault) { e.preventDefault(); }
                    }
                },
                scroll: function (e) {
                    if (typeof settings.moved === 'function') {
                        settings.moved.call($this, settings);
                    }
                    if (e.preventDefault) { e.preventDefault(); }
                },
                inputClick: function (e) {
                    if (Math.abs(settings.velocity) > 0) {
                        e.preventDefault();
                        return false;
                    }
                },
                // prevent drag and drop images in ie
                dragStart: function (e) {
                    if (elementFocused) {
                        return false;
                    }
                }
            };

            attachListeners($this, settings);
            $this.data(SETTINGS_KEY, settings)
                .css("cursor", settings.cursor);

            if (settings.triggerHardware) {
                $this.css({
                    '-webkit-transform': 'translate3d(0,0,0)',
                    '-webkit-perspective': '1000',
                    '-webkit-backface-visibility': 'hidden'
                });
            }
        });
    };

    $.kinetic = {
        settingsKey: SETTINGS_KEY,
        callMethods: {
            start: function (settings, options) {
                var $this = $(this);
                settings = $.extend(settings, options);
                if (settings) {
                    settings.decelerate = false;
                    move($this, settings);
                }
            },
            end: function (settings, options) {
                var $this = $(this);
                if (settings) {
                    settings.decelerate = true;
                }
            },
            stop: function (settings, options) {
                var $this = $(this);
                stop($this, settings);
            },
            detach: function (settings, options) {
                var $this = $(this);
                detachListeners($this, settings);
                $this
                .removeClass(ACTIVE_CLASS)
                .css("cursor", "");
            },
            attach: function (settings, options) {
                var $this = $(this);
                attachListeners($this, settings);
                $this
                .addClass(ACTIVE_CLASS)
                .css("cursor", "move");
            }
        }
    };
    $.fn.kinetic = function (options) {
        if (typeof options === 'string') {
            callOption.apply(this, arguments);
        } else {
            initElements.call(this, options);
        }
        return this;
    };

} (window.jQuery || window.Zepto));
